Heat insulation and process of making same



April 8, wm v msmw R S. BLAIR HEAT INSULATION ANb PROCESS OF MAKING SAMEFiled Aug. 9, 1921 Patented Apr i924.

omrao STATES ROBERT S. BLAIR, OF SOUND BEACH, CONNECTICUT.

HEAT INSULATION AND PROCESS OF MAKING SAME.

Application filed August 9, 1921. Serial No. 491,057.

To all whom it may concern: 7

Be it known that I, ROBERT S. BLAIR, a citizen of the United States, andresiding at Sound Beach, in State of Connecticut, have invented a newand Improved Heat Insulation and Process of Making Same, of which thefollowing specification is a full disclosure.

This invention relates to heat insulating material and more particularlyto blocks of such material used as insulation for appliances which areto be kept at low tempera ture.

One of the objects thereof is to provide heat insulating materialconvenient in form, simple in construction and inexpensive tomanufacture. Another object is to provide a form of heat insulatingmaterial which. may be conveniently used in the construction ofrefrigerating appliances. Another object is to provide a type ofinsulating material, and a method of producing the same in which theinsulating properties of the material itself are combined with thehighly efiicient insulation which may be ob tained by the use of hollowcontainers within which a vacuum is maintained. Other objects are inpart obvious and will be in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements and arrangements of parts and the art whichwill be exemplified in the structure hereinafter described and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of the variouspossible embodiments of this invention, Figure I is a side elevation incross section of the vacuum tank in which the insulating material issubjected to vacuum and at the same time is coated and impregnated to aslight depth with a non-porous material. Figure II is a plan view of thevacuum tank shown in Figure I. Figure III is a greatly enlarged view ofa piece of the insulating material, the section being taken along theedge thereof giving a clear, representation of the air cells containedin the material and the air tight coating over the exterior surface ofthe piece of insulating material.

Similar reference characters refer to similar parts throughout in theseveral views of the drawings;

the county of Fairfield and Turning now to the accompanying drawings, wehave in Figure I at 10 a tank closed at the lower end and provided witha circular opening in the center 0 its upper end which opening can beclosed by means of a cover 11 hinged at its right hand end on the pin 12which is supported in-the lug 13 riveted to the outside of the tank 10by means of rivets such as l-i, the cover 11 being tightly clampedagainst the upper end of the tank 10 by means of the hinged bolts 15which are made in two pieces and are swiveled together on the pin 16.The lower end of the hinged bolts 15 are tapped into the head of thetank 10 and a check nut 17 is threaded on to the lower ends thereofwhere they project through the head of the tank 10, the; upper end ofthe hinged bolts 15 pass through slots in the flange around the edge ofthe cover 11 and by screwing down upon the nut 18 threaded on the endsthereof the cover 11 is firmly held in position. A. soft gasket 19 isinterposed be tween the adjacent surfaces of the upper end of the tank10 and the lower end of the cover 11 insuring an air tight joint beingmaintained. there between when the nuts 18 on the hinged bolts '15 arefirmly screwed down. Four lifting rods 20 pass through stuffing boxes 21positioned in the corners of the tank 10 and at threaded into a basket22; the lifting rods 20 are provided with large eyes at their upper endso that a chain tackle may be hooked thereon to raise or lower thebasket. Blocks such as 23 of balsa wood or pumice stone or some othersimilar porous material, are piled upin the basket 22; spacing piecessuch as 24 of ordinary wood are interposed between the successive layersof blocks of balsa wood or pumice stone such as 23 so that when thebasket 22 is lowered to the lower end of the tank 10 and thoroughlysubmerged in the liquid 28 contained therein all surfaces of the blocksof balsa wood or pumice stone such as 23 will be subjected to the actionthereof.

Communicating with the upper end of the tank 10 by means of the pipe 25is a vacuum pump 26, a three-way valve 27 bein interposed'in the pipe 25between the tan]? 10 and the vacuum pump 26 so that by properlymanipulating the handle thereof the vacuum pump 26 may be connected withof the upper head their lower ends are tie ' the tank or disconnectedtherefrom and a port opened which will permit atmospheric air to rushinto the tank 10 therethrough and break the vacuum existing therein.Turning now to Figure III we have a block of balsa wood or umice stoneor other similar porous materia balsa wood' being preferred, a number ofwhich blocks were shown at 23 in Figure l. The upper corner of the blockhas been cut away and the structure of the material of which the blockis composed has been greatly magnified so that air cells 29 which arecharacteristic of this material are clearly shown together with the cellwalls; the outer surface of the block is covered by an air tight coating30 of rubber, condensite or other similar material which may be had in aliquid form and upon drying will form a durable air tight film.

The action of the apparatus above described is substantially as follows:The nuts 18 on the hinged bolts 15 are unloosened and the upper ends ofthe hinged bolts 15 are swung out of the slots in the cover 11 and thevacuum existing in the tank 10 having been broken by turning the valve27 so that the passageway therethrough lines up with the end of the pipe25 where it connects with the tank 10 thus permitting atmospheric air toflow therethrough bringing the pressure in the tank 10 up to atmosphericpermitting the cover 11 to be now lifted and swung over to the rightabout the pin 12 as an axis. The upper ends of the lifting rods 20 arenow grasped by the operator or in the case of very large apparatus ablock and tackle is hooked therein and by lifting thereon the basket 22is brought up to the upper end of the tank 10. Blocks 23 of porousmaterial consisting of balsa wood, pumice stone or other similar porousmaterial are now laid in well spaced layers in the basket 22; woodspacers such as 24 being interposed between the successive layers of theblocks 23. The basket 22 having been completely filled with layers ofthe blocks of porous material such as 23 the lifting rods 20 are loweredso that the basket 22 connected to the lower ends thereof is lowered andsubmerged completely in the liquid 28 contained in the lower end of thetank 10 which consists of a solution of rubber, condensite or some othermaterial which on drying forms a durable air tight coating. The cover 11is now swung over to the left until it rests upon the upper end of thetank 10 and the upper ends of the hinged bolts 15 are swung over intothe slots in the cover 11 and the nuts 18 securely screwed down. The aircontained in the tan k 10 above the liquid 28 is removed by swmgmg thehandle of the valve 27 over so that the port connecting with theatmosphere is closed and a clear passageway is opened up through thepipe 25 to the vacu- Laeasao uln pump 26 which being continuously inoperation soon reduces the pressure 1n the tank 10 to considerably belowatmospher c. A high degree of vacuum is maintained in the tank 10 for asufficient length of time to permit allthe air contained in the cells ofthe blocks of porous material 23 to be exhausted and after this has beenattained the basket 2-2 is drawn up above the level of the liquid 28 bypulling up the lifting rods 20 and is allowed to rest in this position asufficient length of time to allow the coating left on the exteriorsurfaces of the blocks of porous material 23 by the liquid 28 tosolidify, the surplus draining off into the bottom of the tank 10. Itmay be advantageous to slightly lower the degree of vacuum while thecoating of the liquid 28 on the exterior surfaces of the blocks ofporous material 23 is drying as under this condition the degree ofvacuum existing in the air cells contained therein would be greater thanthe degree of vacuum surrounding them and consequently the coating lefton the exterior surfaces thereof by the liquid 28 would tend to bedriven somewhat into the material and make a firmer coating thereon.Sufficient time having been allowed for the coating left by the liquid28 on the exterior surfaces of the blocks of porous material 23 tobecome thoroughly set, the handle of the valve 27 is swung over breakingthe connection between the tank 10 and the vacuum pump 26 and permittingatmospheric air to rush into the tank 10 breaking the vacuum therein andpermitting the cover 11 then to be raised as previously described. Theblocks of porous material 23 are now removed from the basket 22 and arenow ready to be used as a very efiicient in- I sulating material as theair cells characteristic of this type of porous material now contain airat a very low pressure so that the insulating properties of the blocksof porous material 23 are obtained from the small vacuum cells containedtherein which formerly contained inert air at atmospheric pressure. Asis well known, cells containing inert air at atmospheric or higherpressure are very much less efficient as heat insulators than cellscontaining a greatly rarefied atmosphere.

As various possible embodiments might be made of the above invention andas various changes might be made in the embodiment and the art above setforth, it is to be understood that all material herein set forth orshown in the accompanying drawings is to be interpreted as illustrativeand not in a limiting sense.

I claim:

. 1. The herein described art which consists 1n exhausting air from aporous substance and covering the substance to prevent the re-entry ofthe air.

2. The herein described art which consists in subjecting a poroussubstance to a vacuum, covering it while in the vacuum to prevent there-entry of air after the vacuum 1s removed.

3. The herein described art Which consists in exhausting the air from aporous substance and applying a coating to said substance to prevent there-entry of air.

4. The herein described art which consists in exhausting the air from asubstance and coating said substance with a material which enters theouter pores of the substance over its outer surface and prevents there-entry of air.

5. The herein described art which consists in exhausting the air from aporous substance and impregnating its outer surface with a substance imervious to air.

6. The herein described art which consists in shaping a porous body intoa predetermined form, exhausting the air therefrom and covering itsouter surface to prevent the re-entry of air thereto.

7 As a new article of manufacture, a porous substance having the airexhausted from its pores and a covering about said substance preventingthe re-entry of air.

8. As a new article of manufacture, a porous substance having the airexhausted from its pores and provided with a coating sealing its outersurface and preventing the re-entry of air. I

9. As a new article of manufacture, a porous substance having the airexhausted from its pores and a flexible coating over the surface of saidsubstance preventing the re-ent of air.

10. s a new article of manufacture, a porous substance having the airexhausted from its pores and having its outer portions over its surfaceimpregnated with a suhstance impervious to air.

11. As a new article of-manufacture, a non-metallic porous substancehaving the air exhausted from its pores and a non-metallic coverin overthe surface of said substance preventing the re-entry of air.

12. As a new article of manufacture, a body of. balsa wood having theair exhausted from its pores and a non-metallic coating about the outersurface of said wood pre ventin the re-entry of air.

13. s a new article of manufacture, a body of porous material havingpores of substantial size, the air being exhausted therefrom, and anon-metallic coating about the outersurface of said material preventingthe re-entry of air to said pores.

In witness whereof, I hereunto subscribe my name.

ROBERT S. BLAIR.

